Growth and characterization of zno nanoparticles by sol. The electrical properties and impedance analysis of zno. Degradation analysis of metal oxide varistors under. Nanoscale characterisation of barriers to electron conduction in zno varistor materials. Pdf metal oxide znobased varistor ceramics researchgate. Synthesis of zno based nanopowders via a nonhydrolytic. Zinc oxide varistors are electronic ceramic materials whose electrical behavior is dominated by grainboundary interface states. Among the mechanisms suggested to account for degradation of varistor materials.
Onedimensional zno nanostructures have great potential applications in the fields of optoelectronic and sensor devices. A surge in excess of the specified withstanding surge current may cause short circuits or package rupture with expulsion of material. Analysis of zno varistors prepared by the solgel method. The patterns confirmed the presence of dominant zno phase icsd code. Characterization of the interface states in zno varistors. A comparative study between the effects of magnetic and. The metal oxide znobased varistors are nonlinear ceramic resistors which. Synthesis and characterization of zno nanoparticles of. Zinc oxide varistors are ceramic devices sensitive to transient voltage surges. Mechanism and development of tio2doped znobi2o3based. Electrical properties of zno varistors prepared by direct mixing of constituent phases m.
Thesis for the degree of doctor of philosophy a firstprinciples study of interface systems. A novel varistorcomposite synthesis for the fabrication of high breakdown voltage zno varistors has been successfully developed. Pdf the surge arrester of kv gasinsulated substation gis needs zno varistor with. Jayanta kumar behera, roll no 407ph102 to this institute in partial fulfillment. Insitu quantitative measurement of electric fields in zinc oxide thin films using electrostatic force microscopy jan harloff philadelphia, pennsylvania december, 1995 a thesis presented to the faculty of engineering and applied science of the university of pennsylvania in partial fulfillment of the requirements for the.
Abstract of thesis presented to the senate of universiti putra malaysia in fulfillment of the requirement for the degree of master of science. Zno grains doped with manganese, cobalt and nickel. The cu2o addition deteriorates the electrical properties of zno varistors, which is a good agreement with similar findings on ag2o additions. Allenic a dissertation submitted in partial fulfillment of the requirements for the degree of doctor of philosophy materials science and engineering in the university of michigan 2008 doctoral committee. Study on microstructure and electrical properties of zno. Juan b just0 43m,7mx mar del plata argentina abstract.
The effects of annealing on b 2 o 3contained zno varistors with particular emphasis on the degradation behavior, nonlinear coefficient, trap density, donor density, and schottky energy barrier were investigated. Zno varistor, wattloss, energy absorption capability, non. They are formed through the sintering of a mixture of zno with other oxides, such as bi 2 o 3, sb 2 o 3, coo, mno 2, and cr 2 o 3, among others. B dejene department of physics, university of the free state qwaqwa campus, south africa, za 9866. Chapter vi, which is the core part of this thesis work, is mainly devoted to the characterization study of znobased building blocks. School of mechanical and manufacturing engineering dublin city university. Higher density and strength of a green body are critical not only for handling at its green state but. Structural, electrical and optical properties of ptype zno epitaxial films by arnold l. A thesis submitted to the faculty of engineering and the built environment. The microstructure of a zno varistor material has been investigated by a combination of xray diffractometry and analytical electron microscopy sem, tem, stem, edx. In this work, systematic substitution of zno with sno2 in znobased varistor composition was investigated through analysis of densification, phase formation, microstructure and nonlinear properties. Performance evaluation of zinc oxide varistor produced from powder. In this work, systematic substitution of zno with sno2 in zno based varistor composition was investigated through analysis of densification, phase formation, microstructure and nonlinear properties.
Electrical properties of zno varistors prepared by direct. Electronic properties of metal quantum wells and varistor materials. Zno varistor column inside the metaloxide surge arresters. Characterization and performance evaluation of zinc oxide. Stability of zinc oxide varistors a thesis submitted to the university of manchester for the degree of doctor of philosophy in the faculty of engineering and physical. Under extreme electrical stresses the nonlinear characteristics of a varistor can.
The thermal stability of zno varistors was considerably improved by the thermal annealing process. All material contained within the thesis, including without limitation text, logos. Stability of zinc oxide varistors a thesis submitted to the university of manchester for the degree of doctor of philosophy in the faculty of engineering and physical sciences 2014 poonsuk poosimma school of materials. The main focus of this work was to develop novel industrially viable procedures, based on sol gel technology, for the preparation of nanosize doped zno materials for varistor applications. Jayanta kumar behera, roll no 407ph102 to this institute in partial fulfillment of the requirement for the award of the degree of master of science in department physics, is a bonafied record of the work carried out under my. The zinc oxide zno based varistor ceramics, an electrical protective device. Mohd sabri bin mohd ghazali universiti putra malaysia. This thesis has never previously been submitted for a degree or any other quali cation at this university or any other institution. Structural and morphological properties of validated varistor.
The work presented in this thesis is concerned with the microstructure of. The processing of zno varistor has a long route with numerous contributing variables. Growth and characterization of zno nanoparticles by solgel process a thesis submitted in fulfillment of the requirements for the degree of magister scientiae m. A new solgel processing method to prepare znobased varistor powders, using inexpensive zinc acetate dihydrate, ethylene glycol, npropyl alcohol and glycerol as starting materials, is presented. Rind in the lik degradation in zno varistors m s castro, m a benavente and c m aldao institute of materials science and technology ontema.
Varistor samples containing different amounts of constituent phases were prepared. The effects of heat treatment on b2o3contained zno. Department of science and technology itn, campus norrkoping, linkoping university, se601 74 norrkoping, sweden. Of zno based varistor ceramics doped with rare earth. Technical information physical properties of zinc oxide varistors.
Ebadzadeh4 1 department of ceramic, science and research branch, islamic azad university, tehran, i. Response surface methodology for optimization of sintering process for preparation of zno low. A wide variety of zno varistor options are available to you, there are 275 suppliers who sells zno varistor on, mainly located in asia. This is to certify that the thesis entitled synthesis and characterization of zno nanoparticles is submitted by mr.
Requirements for the degree of doctor of philosophy. This thesis has never previously been submitted for a degree or any other quali cation at. A model of znozno grain boundaries in a zinc oxide varistor. A prototype znobased mov with near ideal vi characteristic can be developed. Powder processing parameters and their influence on the electrical performance of zno varistor begum, shahida 1996 powder processing parameters and their influence on the electrical performance of zno varistor. Comparative study of metal oxide varistors movs for. Thermoionic emission and tunneling are acknowledged to be the major transport mechanisms. Help us write another book on this subject and reach those readers. The binder plays an important role in the fabrication of this electro. The emphasis is given to the fabrication of dense, uniform and defectfree zno layers for the memristive application by. The top countries of suppliers are turkey, china, and south korea, from which the percentage of zno varistor supply is 1%, 97%, and 1% respectively. I, pitshou bokoro, declare that this thesis titled, degradation analysis of metal oxide varistors under harmonic distortion conditions and the work presented in it are my own. Azlin mustapha, thesis supervisor abstract in this study, the effects of zinc oxide zno and silver ag nanoparticles nps on the intestinal bacteria, escherichia coli, lactobacillus acidophilus, and bifidobacterium animalis were investigated.
Comprehensive summaries of uppsala dissertations from the faculty of science and technology 686. Thesis submitted in fulfillment of the requirements for the degree of master of science. Omkar behera 107bt017 in ful llments for the requirements for the award of bachelor of technology degree. Synthesis and characterization of solgel derived zno thin. Pillai tcd thesis 6659 synthesis and characterisation. It was preserved for the fabrication of varistor discs.
Nanoscale characterisation of barriers to electron. This is to certify that the thesis entitled, synthesis and characterisation of zno nanoparticles with various size and their application in biological system submitted by mr. Powder processing parameters and their influence on the electrical performance of zno varistor a thesis submitted to dublin city university in fulfilment of the requirements for the degree of doctor of philosophy by shahida begum, bsc eng name of supervisors prof m s j hashmi dr ramon puyane collaborating establishment harris corporation. Brankovic center for multidisciplinary studies, university of belgrade, kneza viseslava 1, 1 belgrade, serbia abstract. Performance evaluation of zinc oxide varistor produced from powder under different spray drying. The microstructure of a zno varistor material springerlink. Active zinc oxide by calcination of a carbonate low crystallinity zno with high speci. The microstructure and xrd patterns of the zno varistor samples sintered at 1150 c for 1 h are shown in figs. Synthesis and characterisation of nanocrystalline zno for. Influence of adding sic on microstructure and electrical.
Carlsson experimental physics, school of physics and engineering physics, chalmers university of technology and g oteborg university, gothenburg, sweden 2002. Higher density and strength of a green body are critical not only for handling at its green state but also to avoid the causes of flaw formation during sintering. The experimental results show that the spinel phase zn7sb2o12 generated during sintering. The arrhenius plots of the emission rate gave the depths of the interface states of 1.
Metal oxide znobased varistor ceramics, advances in ceramics electric and magnetic ceramics, bioceramics, ceramics and environment, costas sikalidis, intechopen, doi. Zno zno grain boundary, rich of bismuth, which is a highly resistive phase, is the main cause of. The resultant product is a polycrystalline ceramic with a unique grainboundary property, which is responsible for the nonlinear iv characteristics of. Several conduction mechanisms for the varistor have been proposed based on this ceramic microstructure 1,2,6, which has led. Improvement of the vi characteristic of zinc oxide zno. Both bi 2o 3rich and zn 7sb 2o 12 spinel phases are also usually present at the grain boundaries of the zno, but the presence of a bi 3zn 2sb3o14 phase is possible as well. Effect of compaction parameters and sintering configurations on the performance of zno varistor a thesis submitted in fulfilment of the requirements for the degree of doctor of philosophy to dublin city university by a n mustafizul karim, b. The best fitted impedance analysis reveals that the cu2o addition increases grain resistance and lowers the grain boundary resistance, results in low nonlinearity and higher leakage current of zno varistors. Unpublished msc thesis, school of materials engineering, northern malaysia. Characterization of znodegraded varistors used in high. School of engineering, cardiff university united kingdom january 2017. They exhibit a highly nonlinear currentvoltage relation with a 5%. It involves coating zno nanoparticles with sio2 through the hydrolysis of tetraethyl orthosilicate teos and the subsequent coating of additives on the core of the sio2coated zn.
Exploration of zno and znmgozno thin film transistors. It was found that the zno luminescence green and yellow decrease with increase in annealing. Investigation of electrical properties of field grading materials based zno microvaristors a thesis submitted to cardiff university in the candidature for the degree of doctor of philosophy by hafisoh ahmad, b. Under extreme electrical stresses the nonlinear characteristics of. Mechanism and development of tio2doped zno bi2o3based varistors 81 layer in the grain on both sides of the interface. Although both mn and al do not influence the wellknown peaks related to wurtzite structure of zno ceramics, some other unknown peaks could be formed at higher doping content. Figure 4 represents the xrd spectrum of the validated polycrystalline ceramic used as core in zno based lowvoltage varistor. The effects of zinc oxide and silver nanoparticles on intestinal bacteria ami yoo dr. Exploration of zno and znmgozno thin film transistors henning kittang remme thesis submitted in partial fulfillment of the requirements for the degree master of. Mechanism and development of tio2doped znobi2o3based varistors 81 layer in the grain on both sides of the interface.
A comparative study between effects of mn and al on the properties of zno varistor sintered at 1200 is investigated by xrd, sem hardness, and iv measurements. Submitted to university of baghdad college of education for pure. Manufacturing of zinc oxide varistors zinc oxide varistors are ceramic. Recent research developments in sno2based varistors. The work presented in this thesis is concerned with the microstructure of zinc oxide varistor materials used in surge protecting devices. Figure 4 represents the xrd spectrum of the validated polycrystalline ceramic used as core in znobased lowvoltage varistor. Changes in the intensity of green and yellow luminescence centers were studied as a function of annealing treatment. It was found that the zno luminescence green and yellow decrease with increase in annealing temperature, reach a. Microstructural analysis of znopr6o11nd2o3 varistor. Metal oxide zno based varistor ceramics 331 conductors. Synthesis and characterization of zno nanostructures. The effects of zinc oxide microstructure on the electrical characteristics of lowvoltage ceramic varistors kesan mikrostruktur zink oksida terhadap ciriciri elektrik varistor seramik voltan rendah by shahrom mahmud thesis submitted in fulfillment of the requirements for the degree of master of science january 2004. Synthesis and characterization of zno nanoparticles.
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